Management for Water Quality on Rangelands Through Best Management Practices: The Idaho Approach

Abstract

Nonpoint sources of pollution from rangelands are becoming a steadily larger public issue. Recent water quality concerns, notably the 1987 Clean Water Act, have impelled states to address nonpoint control, chiefly through best management practices (BMPs) to reach water quality goals. Rangeland BMPs are based on study and experience gained from observing the effects of grazing management and range improvements on the hydrological processes of watershed uplands and riparian zones. Grazing practices providing moderate grazing intensity within a system that includes seasonal rotation and periodic rest will tend to maximize infiltration rates and decrease sediment production from uplands through production of increased biomass. The same approach will tend to reduce effects at the four main riparian points of stress (riparian vegetation, channel morphology, water column, and streambanks). Virtually every range improvement technique, properly conducted, is a potential BMP for abatement of nonpoint source pollution. Nearly all rangeland BMPs must be based on a professional understanding of ecological principles.

Idaho is leading state efforts to improve nonpoint source abatement of pollution. The state has adopted a rather complex but fairly effective two-pronged approach consisting of stream protection and pollution control. Under the latter effort, Idaho has developed an antidegradation policy and water quality standards. BMPs are the chief management instrument, combined with long-term monitoring and feedback processes to make incremental changes. The agricultural (including grazing) water quality program to reduce nonpoint source pollution relies on voluntary, cost-share-encouraged cooperation through soil conservation districts. Given the scale of the problem, this is probably the only feasible approach, and is likely to produce tangible results in the years ahead.